Drive circuit and display device

Abstract

A drive circuit includes: an input-side inverter circuit and an output-side inverter circuit connected to each other in series and inserted between a high voltage line and a low voltage line. The output-side inverter circuit includes a CMOS transistor having a first gate and a second gate, in which a drain is connected to the high voltage line side and a source is connected to an output side of the output-side inverter circuit. The output-side inverter circuit further includes a MOS transistor in which a drain is connected to the low voltage line side and a source is connected to the output side of the output-side inverter circuit. The output-side inverter circuit further includes a correction circuit correcting a voltage of one or both of the two gates of the CMOS transistor.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a drive circuit suitably applicable to a display device that uses, for example, an organic Electro Luminescence (EL) element. The present invention also relates to a display device having the drive circuit.[0003]2. Description of the Related Art[0004]In recent years, in the field of display devices displaying images, a display device that uses, as a light emitting element, an optical element of current-driven type whose light emission intensity changes according to the value of a flowing current, e.g. an organic EL element, has been developed, and its commercialization is proceeding. In contrast to a liquid crystal device and the like, the organic EL element is a self-light-emitting element. Therefore, in the display device using the organic EL element (organic EL display device), gradation of coloring is achieved by controlling the value of a current flowing in the organic EL element.[0...

AI Technical Summary

Benefits of technology

[0014]In view of the foregoing, it is desirable to provide a drive circuit capable of reducing a variation in the timing of a rise in an output voltage, and a display device including this drive circuit.

[0018]According to the above-described drive circuit and the display device of the embodiments, in one or both of the two gates of the CMOS transistor, the voltage corresponding to the threshold voltage of the CMOS transistor can be set as an offset. Thus, a variation can be reduced in timing of a rise in the output voltage of the drive circuit. Therefore, for example, in an organic EL display device, a variation in a current flowing in an organic EL element at the time of light emission can be reduced and thus, uniformity of intensity can be improved.

Problems solved by technology

Therefore, there is such a problem that when, for example, the timing of a rise in the voltage Vout of the output OUT varies and a mobility correction period ΔT varies by Δt1 or Δt2, a current Ids at the time of light emission varies by ΔIds as illustrated in, for example, FIG. 24, and this variation leads to a variation in intensity.

Incidentally, the problem of the variation in the threshold voltage Vth not only occurs in the scan circuit of the display device, but also similarly occurs in other device.

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